Baseboard heater



May 2 1957 R. F. KNUDsoN ETAL. 3,317,707

BASEBOARD HEATER 2 Sheets-Sheet l Filed Aug. 24, 1964 4 W w W ms N R 560 0 mwNM r VKO@ 7 w. 4m 4 M a @uw @FZ May 2, 1.957 R. F. KNUDSON ETAL 3,317,707

BASEBOARD HEATER 2 Sheets-Sheet 3 Filed Aug. 24, 1964 United States Patent O 3,317,707 BASEBOARD HEATER Robert F. Knudson, Concord, and Eugene R. Long, Marshall, Mich., and Lucas G. Tramontana, Oxford, Miss., assignors to McGraw-Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Aug. 24, 1964, Ser. No. 391,700 3 Claims. (Cl. 219-367) This invention relates to Ibaseboard heating units and more particularly to an improved mounting assembly for such units.

In an electrical baseboard heating unit which is a device having ostensibly no moving parts a major problem is the noise caused by differing amounts of expansion as a result of differing temperatures in various parts and diftering materials. It is common practice to use an aluminum extrusion to form the body portion of the heater assembly with the result that the heater assembly has a greater coeflicient of expansion which combines with its attaining a higher temperature during a heating cycle to cause friction, wear and noise during operation.

The applicants have provided a mounting structure that has positive stability provided by a fixed support location and utilizes one or more locations of loosely confining friction free support to accommodate the irregular rates of expansion without noise or excessive wear.

It is an object of this invention to provide a baseboard heatingmounting structure that eliminates noise and wear during heating and cooling cycles.

It is a further object of this invention to provide a baseboard heater assembly wherein the heater element assembly is positively positioned and supported.

These and other objects and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawings, wherein:

FIG. l is a front elevation of the heating element reflector assembly with portions broken away and the front shield shown in phantom view;

FIG. 2 is a section view of an electrical baseboard heating unit incorporating the mounting assembly of this invention;

FIG. 3 is a section View taken along line 3-3 of FIG. l showing an expansion support location;

FIG. 4 is a section view taken along line 4-4 of FIG. l showing a stationary support location;

FIG. 5 is a view of a weld screw utilized at the heater support location.

Referring to the drawings two or more weld screws as seen in FIG. 5 are inserted into accurately positioned apertures in a channel shaped reflector 11 (FIGS. 2 thru 4) to provide supporting locations for the heater assembly 13. The electric heater assembly 13 is formed of an aluminum extrusion 14 having a pair of U-shaped channels into which the aluminum sheathed heating element 16 is inserted. Following insertion of the sheathed heating element the flanges 17 of the U-shaped channel are crimped down to hold the heating element captive as shown in the section views of FIGS 2 thru 4. The common material of the sheath and extrusion and the intimate contact therebetween eliminate unequal expansion or noise arising from the contact between these heater assembly elements. A single sheathed heating element may be utilized with a hairpin turn as shown in FIG. l or a pair of straight elements may be utilized which are interconnected at one end.

Referring to FIG. 1 the baseboard assembly is composed of a single stationary support location as indicated by the central bolt 10a and one or more expansion locations as shown by the bolts 10b which extend through the slotted openings 19 of the heating element assembly.

3,317,707 Patented May 2, 1967 ICC The mounting illustrated is a longer unit such as five to eight foot lengths wherein two expansion mountings are utilized in addition to the single stationary mounting. In shorter units, such as those three and four feet in length, it is only necessary to use a single expansion mounting in conjunction with a stationary mounting to provide two locations of support.

Referring to FIG. 3 an expansion support location is assembled by first projection welding the weld screw 10b to the reflector 11. A positioning washer 21 is then assembled about the weld screw which fits over the unthreaded cylindrical portion 23 and is restrained against furthur axial movement toward the reflector by the first spacing stop or shoulder 25. Washer 21 provides for accurately positioning the heater assembly 13 at a fixed minimum distance from the reflector 11 and is further plated so as to present a large smooth bearing surface facing the heater assembly. A brass sleeve or roller 26 is then assembled over the unthreaded portion 23 of the weld screw 10b between the second positioning stop or shoulder 29 and the positioning washer 21. The heating element assembly 13 is assembled about the bushing 26 with the spacing between the parallel edges of the slotted opening 19 being slightly greater than the outside diameter of the bushing so that only one parallel surface of the slot may contact the bushing at a given time. Sleeve 26 is rotatable with respect to the weld pin and acts as a journal bearing to reduce the wear on the comparatively soft aluminum extrusion 14 of the heating element assembly 13 that would occur due to the sawing action of the heating element assembly across the weld pin as heating and cooling cause unequal expansion and contraction of theheating element with respect to the supporting reflector. A flange nut 31 is assembled about the threaded end of the weld screw 10b and tightened against the second spacing stop or shoulder 29 to provide a second confining surface which cooperates with the positioning washer to loosely but accurately confine the heating element assembly and establish a maximum spacing with respect to the reflector 11. Flange nut 31 is also plated to assure that a smooth axial surface will confront the heater assembly.

A front shield 33 may be mounted in spaced relation to the heater assembly confronting the side opposite the reflector. Such a shield is utilized on higher density wattage models and functions to increase air flow across the heater assembly, to act as a secondary heat transfer surface and to reduce the cabinet front panel temperatures by acting as a radiation shield. The front shield 33 has accurately located clearance holes with a similar center to center spacing as the apertures in the reflector and is assembled over the weld screws 10 with the flange nut 31 acting as a stop in the debossed area to position the front shield in relation to the heater assembly 13 with the shield held in place by a nut 37 which retains the shield against the flange nut 31. It will be noted that the front shield is positively and rigidly associated with the reflector 11. The front shield and reflector being on opposite sides of the heater assembly at about the same effective distance and being of similar materials expand and contract at virtually the same rate. Sin-ceI there is no relative movement between them during heating and cooling cycles it is unnecessary to provide for relative movement.

Referring to FIG. 4 the stationary mounting location is shown wherein an identical weld screw 10a is projection welded to the reflectorll and a positioning washer 21a assembled on the weld screw against the first stop shoulder 25a. At the stationary location the heating element assembly is assembled over the Unthreaded portion against the stop washer 21a and a second washer 39 is installed over the unthreaded portion which extends axially out about the threaded portion so that by tightly securing the ilange nut 31a against the washer the heater assembly is compressed between the washers 21a and 39 and maintained in a stationary condition. The clamping action of this stationary position prevents the heater assembly from rocking back and forth relative to the reflector.

Referring to FIG. 1 the centrally positioned stationary location positively positions the heating element assembly with respect to the reector while the expansion connections at either end accept the expansion of the heater element with respect to the reflector smoothly and quietly without binding or clamping action during both heating and cooling cycles. Further by placing the stationary location at the center position the longitudinal movement due to the irregular expansion of the subassemblies is minimized and only half the total expansion need be accepted by the expansion support location adjacent to either end.

In FIG. 2 the Ieector element assembly is shown mounted in a housing 41 with the radiation shield 11 spaced from the housing rear wall 42 and secured in position by lower brackets 43 which have upturned flanges received in slotted apertures in the shield 11 and upper brackets 44 to which the shield is bolted. The housing front panel 45 is provided with upper and lower apertures 46 and 47 respectively to aiford convective air flow over the heating element.

Although but one embodiment has been shown and described it will be apparent to -those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims,

What is claimed is:

1. A baseboard heater assembly comprising a longitudinally extending member; first and second bolts mounted on and projecting from said longitudinally extending member; a heating element assembly having tirst and second longitudinally spaced apertures therein; said first bolt projecting through said first aperture with fastening means carried by said first bolt securing said heating element assembly in a predetermined laterally spaced relation with respect to said longitudinally extending member; said second aperture being longitudinally elongated; said second bolt having a rst shank portion, a reduced diameter second shank portion, and a distal threaded end portion; a positioning washer journaled about said second shank portion; a cylindrical sleeve journaled about said second shank portion intermediate said positioning washer and said threaded end portion, said sleeve and said second shank portion being disposed in said second aperture; and a nut threadably received about said threaded end and presenting an axial surface confronting said positioning washer and spaced therefrom a distance greater than the thickness of said heating element at said second aperture and the axial length of said sleeve.

2. The baseboard heater of claim 1 further comprising a horizontally extending housing surrounding said longitudinally extending member and heating element assembly having a rear wall and a front wall and a longtiudanally extending shield xedly secured to said longitudinally exJ tending member and disposed intermediate said heating element assembly and said front wall, said longitudinally extending member being of channel shaped section having a vertical lwall and generally horizontally extending flange portions with said heating element assembly being disposed between said generally horizontally extending ange portions, said horizontally extending member being mounted on said rear wall in horizontally spaced relation thereto.

3. The baseboard heater of claim 2 wherein said longitudinally extending shield is secured about 4the distal ends of said first and second bolts.

References Cited by the Examiner UNITED STATES PATENTS 1,721,099 7/1929 Wiegand 219-536 2,833,905 5/1958 Kenney 219--368 X 2,835,478 5/1958 Bemish 165-55 2,924,693 2/1960 Ripley 219-342 X 2,944,138 7/1960 Goff 219-367 X 2,976,389 3/1961 Burger et al 219--367 X 3,020,382 2/1962 Harrell 219-366 X 3,132,230 5/1964 Laug 2l9366 ANTHONY BARTIS, Primary Examiner'. 

1. A BASEBOARD HEATER ASSEMBLY COMPRISING A LONGITUDINALLY EXTENDING MEMBER; FIRST AND SECOND BOLTS MOUNTED ON AND PROJECTING FROM SAID LONGITUDINALLY EXTENDING MEMBER; A HEATING ELEMENT ASSEMBLY HAVING FIRST AND SECOND LONGITUDINALLY SPACED APERTURES THEREIN; SAID FIRST BOLT PROJECTING THROUGH SAID FIRST APERTURE WITH FASTENING MEANS CARRIED BY SAID FIRST BOLT SECURING SAID HEATING ELEMENT ASSEMBLY IN A PREDETERMINED LATERALLY SPACED RELATION WITH RESPECT TO SAID LONGITUDINALLY EXTENDING MEMBER; SAID SECOND APERTURE BEING LONGITUDINALLY ELONGATED; SAID SECOND BOLT HAVING A FIRST SHANK PORTION, A REDUCED DIAMETER SECOND SHANK PORTION, AND A DISTAL THREADED END PORTION; A POSITIONING WASHER JOURNALED ABOUT SAID SECOND SHANK PORTION; A CYLINDRICAL SLEEVE JOURNALED ABOUT SAID SECOND SHANK PORTION INTERMEDIATE SAID POSITIONING WASHER AND SAID THREADED END PORTION, SAID SLEEVE AND SAID SECOND SHANK PORTION BEING DISPOSED IN SAID SECOND APERTURE; AND 